Mark Pettini's perfectly paced half-century helped Essex back to top spot and handed Somerset a fifth defeat in eight.
Kent escaped with a warning from an ECB pitch panel after their 10-wicket victory over Derbyshire at Canterbury.
Gary Wilson impressed with an unbeaten 160 to put Surrey in a strong position on day two against Leicestershire.
Glamorgan openers Jacques Rudolph and Will Bragg made hay in the Bristol sunshine against Gloucestershire.
Kevin Pietersen's Surrey beat Glamorgan but he once again struggled to make an impact in Friday's encounter.
James Vince cracked 240 as Hampshire thrashed Essex by 470 runs inside three days to boost their promotion hopes.
Surrey and Hampshire took complete control of their respective Division Two fixtures on Monday.
Hampshire finished the first day in the ascendancy after making 286 all out and then reducing Essex to 55-2 at stumps.
England off-spinner James Tredwell has joined Sussex on a month’s loan from Kent to play in the LV= County Championship.
Somerset secure a dramatic one-run win over leaders Hampshire while Glamorgan and Kent shared the spoils in thriller.
Ravi Bopara hit an unbeaten 81 from 44 balls as Essex beat Kent by six wickets in the NatWest T20 Blast South Division.
Saeed Ajmal put promotion rivals Hampshire in a spin to boost Worcestershire’s chances of forcing a victory at New Road.
Surrey finished the opening day with a first-innings lead at Bristol, while Worcestershire are on top against Hampshire.
Ravi Bopara and Tom Westley both hit hundreds as Essex responded superbly on day two against Kent.
A century from Darren Stevens helped Kent to 344-7 at stumps on day one of their Division Two match with Essex.
Kevin Pietersen made just five runs on his return to English cricket as Surrey suffered a five-wicket defeat by Essex.
Michael Carberry led the way with a knock of 73 as Hampshire beat Kent by 22 runs in the NatWest T20 Blast.
Surrey piled more Twenty20 misery on London rivals Middlesex with a six-wicket win in the NatWest T20 Blast.
Surrey move ahead of Essex on a rain-shortened third day of their LV= County Championship clash at Chelmsford.
Glamorgan turned the screw against Leicestershire but rain held up the progress of the three other second-tier fixtures.
Gareth Batty finished with career-best figures of 8-68 as Surrey bowled Essex out for 228 on day one at Chelmsford.
Essex pulled off a dramatic victory over Glamorgan, while there were wins for Kent, Gloucestershire and Hampshire.
Gloucestershire have signed former England wicketkeeper Geraint Jones from Kent on a short-term loan deal.
Hampshire beat Leicestershire to reclaim top spot in Division Two, while Gloucs saw off Kent for their first win.
Saeed Ajmal took 13 wickets as Worcestershire beat Essex by 72 runs on day three of their clash at New Road.